Hello again guys! I would like to ask for your advise for i am really new to using this Arduino microcontroller and wireless transmitter/receiver module.

My project is to monitor soils' temperature, ph, and moisture with its specific feedback. I will be using arduino Mega to be interface with the above needed sensors. My goal is to log all the data that have been read by the sensors. Since the sensors are in the field, i would just like to monitor the soil in our house and decided to wirelessly transmit the read data through a wireless tx/rx module directly to our Personal computer and save it (data logger). I also not prefer to use wifi shield technology, since we are not connected to internet.

Scenario: Sensors=>Arduino=>Transmitter module=>Receiver module=>PC

Will it be possible? Could you suggest what transceiver to use and what other things i need to understand.Please do enlighten me.Thanks a lot.

If you have a field sensor, you can use a simple UNO and a RTC shield with SD card and do data logging.

you can add any RF bits, lots of notes about those on here and I am sure some others will post links.

the question is about distance. if your garden is in the back yard, you do not need to worry about distance as it will be so short.

if your garden is acres upon acres, you can create a mesh and have the furthest one send it's data to the one closer, to the one even closer and so on.

if your garden is disperse and you do not have the easy links, you can look into LoRa, somewhat new, but you can send data over long distances.

watch some youtube on people using sensors over long distances.

it would be remiss of me if I did not point out your error on WiFi. you can have two ESP8266 modules use their wifi to talk to each other. you do not have to have the internet. they consume lots more power [than most RF units] when communicating, so battery power does come into play.

I would offer that you should start with an UNO, the RTC shield and SD card to get all the sensors working. get the data you want, check the frequency of the data, no need to get 60 second updates on temperature or soil moisture when hourly or daily is all you really need.

You can get a lot of those up and running and then add wireless as you go.

WiFi doesn't necessarily need an Internet connection. Just create your own local network.

250 meters can be done with WiFi but needs line of sight. The same will account for most other wireless communication, it's quite a distance. Buildings or (worse) a hill in between will be a problem. Trees may be a problem.

Obstruction is also one of my problem here. The monitoring site is covered by my neighbor's houses. I look also on zigbee series, but nrf is more cheaper and low powered but still new yet. Well the system will be monitor for 24 hrs and as mentioned wifi shield has a high power requirement. Still looking for other transceivers.

Using a mobile phone network for data transmission may be another option, especially if you don't have a decent line of sight.

Anyway, those modules come really cheap. The NodeMCU boards (with ESP8266 processor) sell at a few USD a piece, the 433 MHz modules likely cheaper. Get some and see how far you get, that helps a lot in making an informed decision on how to do your project.

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